Electromagnetic relay and armature therefor



Sept. 19, 1950 K. w. GRAYBILL ELECTROMAGNETIC RELAY AND ARMATURE THEREFOR .Qtiginal Filed July 13,

. Y 9 mm QM B R m m W6 A w. H T E N N E K Patented Sept. 19, 1950 Q ELECTROMAGNETIC RELAY AND ARMATURE THEREFOR Kenneth Wayne 'Graybill, Elmhurst, Ill., assignor to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Original application July 13, 1946, Serial No.

683,304. Divided and this application December 26, 1947, Serial No. 793,897

2 Claims.

The present invention relates in general to electromagnetic relays in general and more particularly to the construction and mounting of the armature with respect to the relay winding and core of the electromagnet.

This application is a division of my copending application Serial No. 683,304 filed July 13, 1946,

now Patent No. 2,515,769, wherein the specific improvements relating to a multi-contact relay is being claimed.

An object of this invention is to provide an electromagnetic relay in which the armature is attached to the supporting frame by a spring member which is tensioned to retain the armature poles away from the magnet core when the relay is deenergized.

A feature of this invention is the method of adjusting the air gap between the armature and core. The armature is mounted on a spring reed which is attached to the mounting base and therefore has a fixed normal position, in consequence the core is adjusted in relation to the fixed position of the armature by providing space in the core mounting holes so that the core may be moved after the mounting screws have been loosened.

The novel characteristics of this invention, the advantages of its particular methods of construction and its operating features will be understood from the following explanation and the reference to the drawings, which consist of fifteen figures on two sheets.

Figure 1 is a top view of a bar relay equipped with thirty-five pairs of make contacts using round wire springs.

Figure 2 is an end view of the relay of Figure 1 taken from the right.

Figure 3 is a bottom view of the relay of Fig ure 1.

Figure 4 is a view of the armature assembly which includes the spring reed hinge.

The embodiment illustrated and described herein consists of a self-contained mechanism including a U-shaped base plate I of a material having a high reluctance to magnetism, a coil core 3| of magnetic iron extending across the open part of the U-shaped base, a coil 38 wound around the center portion of the core 3|, a U- shaped armature 30 of material having a low reluctance to magnetism and two parallel rows of round wire springs.

The center portion of the U-shaped armature 30 is solidly attached to that side of the H -shaped reed armature spring opposite the side which is anchored in the spring pile-up, the H-shaped the core 3! between the two spool heads.

spring being tensioned to maintain the two ends of the U-shaped armature away from the pole pieces of the core 3|.

In Figure 1, which is a top view of a bar relay with thirty-five pairs of round wire contact springs and one pair of leading-in wires, a very substantial base plate I has been provided, upon which the various parts are mounted. Portions of the right and left sides of this base are turned up at right angles to the base to form side members 2 and 3, these members being extended at one end beyond the bottom part of the base and turned at right angles to form lugs 4 and 5 which are equipped with threaded holes 6 and I for mounting the relay on the supporting frame work.(not shown) of the telephone switchboard.

Two other portions of the base plate 8 and 9 have been turned up at right angles to the base to form mounting brackets for the coil core 3| of the electromagnet. It will be noted that core 3| is longer than the coil 38 and the former is square in shape. This square shaped core 3| is provided with two screw mounting holes (not shown) which are larger in diameter than the mounting screws ID to provide adjusting means. The coil spool ends 32 and 33 of insulating material are placed into position on the core and then staked to hold same in position, after which the proper amount of wire to form the coil is wound around Each spool end is provided with a lug or wire terminal 20.

The back stop bracket for the support of the back stop comb I1 is composed of two side mem bers l3 and M, a front member l5 and a rear member IS, the latter is assembled in the spring pile-up, one end of which may be seen in Figure 2. The front member I5 is turned down at right angles to the two side members I3 and I4, to form a mounting surface for the back stop insulating comb I! which is attached by a plurality of rivets l8. It will be noted from Figures 1 and 2 that the front member l5 of the back stop bracket together with the comb I! attached thereto, may be raised or lowered in relation to the base I and armature 30 by the helical springs 25 and the adjusting screws 26. Thus the air gap between the surfaces of the round wire springs 50 and may be regulated. One end of the helical spring 2 5 rests on the top surface of base plate I and its upper end is supporting a side member M of the back stop bracket. The screws 26 pass through holes in member 15, through the hollow center of the helical springs and into threaded holes in the base I.

In the end view Figure 2, it will be noted that the round wire springs 60 of the top row are clamped near one end in the spring pile-up and resting near their free end on the insulatin back stop comb .17, which as previously mentioned, is attached by rivetsrIB to the front-member I of the back stop bracket. The bottom row of round wire contact springs 50 pass diagonally through the moulded insulators of the spring pile-up and are firmly clamped therein. These springs rest near their contact end on the armature comb 42 which is supported by the-armature bracket 43. This bracket 43 is attached to the armature by two screws 28, each being supplied with a spring washer 29. These screws 28 pass through the elongated holes in the armature and into threaded holes 55 in the armature comb bracket 43, thus the bracket 43 together with insulating comb 42 can be moved from left to right and vice versa to move thecomb 42 together with the lower row of round wiresprings 50to align these springs with the respectively numbered springs in the top row. Theadjusting feature for the air gap between the armature 30 and coil core 3|, canbe seen in Figure 2. It will be noted that the two ends of the armature comb: bracket 43, extend to the left and right (as. seen in Figures 1 and 2) beyond the edge oftheicut away portion of base I and therefore comes to rest, when the coil is de-energized, on the top surface of the base plate I, this limits the downward movement of armature 30 underpressure of armature reed spring 40 and results in a fixed normal position for the armature 30; The core 3I is therefore adjusted inrelation to the fixed position of armature 30, by loosening the two screws IIJ'near the ends of core 3I and'moving these ends either up or down. Thetscrews IIJ' pass through enlarged holes in ends3I of the core to permit thisadjustment.

Figure 3 is a bottom view of the relay of Figure 1 disclosing certain of the novel features. Thelower part'of the cutaway portion of the base I can be noted. This is wide enough to allow free movement of that side of the armature which is attached to the edge of the cut away portion by the armature spring 40. Two portionssof this spring 40 can be seen in Figure.3.' These are also seen in Figure 4, being the :portions between the elongated hole 48 and the5edges 46*and 41; The'airspaces 34, in Figure 3, it will be noted, are narrower than the air.space'and'while this construction allows perfect freedom of'movement of the armature, it'limits an endthrust'movement which might be caused'accidentally if therelay should be dropped. In case the relay should be accidentally dropped'and should strike the floor first on one ofthe' U-shaped arms 44 or 45' (Fig. 4), the spring 'wou1d flex at its narrow neck portions 46" and 41 but'not beyond its elastic limit because of' the limited air space 34 between the frame I and the armature 30; The bottom edge of the armature 40 (Fig. 3) would strike the step (or steps) in the frame adjacent the air gaps 34 to limit the flexing of the spring 30 from such a fall. The spring 40 is, therefore, protected against bending beyond its elastic limits in case the relay should be accidentally dropped.

The circles 36 represent embossed portions which furnish slight'projections (not shown) on the opposite, or upper side of 'thebase plate I, to form guides't'o'prevent any end to end movementiof the armature reed spring 40 when same is assembled in the spring pile-up, holes 65 and 66 being provided in spring 40 to receive the raised projections. Due to the fact that the screws 28 pass through elongated holes in the armature 30 to threaded holes 55 in the comb bracket 43, a hole 39 is provided as a guide for instantly determining the normal setting of the comb bracket 43 in relation to either side of the armature 30 prior to the assembly of the armature and its armature reed spring 40 onto the base plate I.

It should be noted that the armature 30 is longer than the coil-38, and that a section has been away from its upper edge (as seen in Figures 3 and 4) from point 44 to 45, leavin the two end sections far enough apart to completely span coil 38; As previously stated, the core ends extend beyond the ends of the coil 38 and when the coil is energized, one section of the armature 30comes in contact with one pole of the magnet core 3I and the other section of the armature comes into contact with the opposite pole of the core 3|. At points 4I (Figure 4) small non-adjustable residuals are fixed to the armature 30 to perform the usual function of preventing the armature from sticking to the pole pieces after the coil has been de-energized.

Figure 4 shows a top view' of the armature assembly including the armature comb bracket 43 and the armature reed spring 40; One portion of the spring is riveted to the armature by a plurality of rivets 49 and another portion is assembled in the spring pile-up and held rigid to the base I. It serves as a hinge for the up and down movement of the armature and therefore the armature does not require one of the ordinary forms of pivot mounting. The spring tension restores the armature to normal when the coil is lie-energized and no other armature restoring arrangement is necessary. The'special construction, comprising two cut away portions, leaving a narrow neck between points 46 and 41 together with the elongated hole 48 provides satisfactory operation as well as considerable ruggedness to guard against damage which might be caused by careless handling.

Attached to the armature and near its center, is the right angle shaped bracket 43 to support the armature comb 42. An end view of bracket 43 can be seen in Figure 2, it being attached to the armature 30 by a plurality of screws 28. should be noted that the bracket 43 has threaded holes 55 to receive the screws 28, which pass through elongated holes in the armature to provide adjusting means. The armature comb 42 is attached to bracket 43 by a plurality of rivets 56 seen in Figure 4. Comb 42 is serrated on its top edge to space apart and form a back stop against the spring pressure of all-of1theround wire springs, such as 50, which comprise the lower half of all the sets of springs.

This is a simple, rugged, and powerful relay and when a current of proper voltage is applied in accordance with the coilwinding, it will operate to lift its armature to close the air gap between the two core poles and the two end sections of the armature and at the same time raising the armature comb with thirty-five round wire springs to make contact with thirty-five stationary round wire springs to close thirty-five electrical contacts. While 35 pairs of springs have been described in this embodiment, it should be understood that different numbers of springs may be used, and that other minor changes may be made without departing from" the spirit of the invention.

What is claimed is:

1. An electromagnet comprising a straight core having flat ends and a middle portion, an energizing winding for said core mounted on said middle portion, a flat U-shaped armature cooperatively associated with said core and having extension arms at one end thereof forming the U- shaped arms thereof and having a recessed middle portion forming the bottom of the U-shape to provide mounting space for mounting said winding on said core whereby said winding lies within said recessed middle portion of said armature, a non-magnetic U-shaped supporting frame having extension arms for mounting the ends of said core and having a recessed middle portion somewhat larger than the other end of said armature; a flat spring having an upper enlarged portion attached to said other end of said armature, a lower enlarged portion attached to said frame below said recessed middle portion of said frame, and a narrow neck portion near the center of said spring between said upper and lower enlarged portions for mounting the said other end of said armature to said frame and within said recessed middle portion of said frame, said narrow neck spring portion having sufficient rigidity to correctly position said armature and hold it in alignment with said frame when said winding is deenergized while permitting pivoting of said armature at said neck spring portion to allow both said armature extension arms to fully operate and engage their associate core ends when the winding is energized.

2. An electromagnet as claimed in claim 1 including a pair of steps provided in said recessed middle portion of said frame, said steps being located on both sides of said narrow neck spring portion and extending to within a predetermined distance of the said other end of said armature to provide stops for limiting the movement of said armature to said predetermined distance to thereby prevent bending of said narrow neck spring portion beyond its elastic limit in case the electromagnet is accidently dropped, and a cutout portion provided in said recessed middle portion of saidframe between said steps, said outout portion being centrally located in said recessed middle portion of said frame adjacent said narrow neck spring portion to provide space to increase the length and flexibility of said spring at said narrow neck portion.

KENNETH WAYNE GRAYBILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 493,620 Freir Mar. 14, 1893 686,007 Shoemaker Nov. 5, 1901 1,994,671 Slawik Mar. 19, 1935 2,169,740 Peek Aug. 25, 1937 2,308,433 McLoughlin Jan. 12, 1943 2,458,247 Bryan Jan. 4, 1949 FOREIGN PATENTS Number Country Date 543,190 Great Britain Feb. 13, 1942 

